Aquaculture has become one of the fastest growing segments of food animal production in the world. This precipitous increase is being driven by decreasing stocks within wild fisheries and increasing demand for seafood throughout the United States, Europe, and Japan. Disease in aquatic invertebrates is a serious problem for the industry.
For example, one of the fastest growing areas of demand is imported farm raised shrimp. According to FAO data, the last twenty years has seen farmed aquatic and in particular farmed shrimp production of Litopenaeus vannamei, commonly the Pacific White Shrimp or the Pacific Whiteleg Shrimp, rise from 8000 metric tons in 1980 to 1,380,000 metric tons produced in 2004 Fisheries and Aquaculture Department. FishStatPlus—Fishery Statistical software 2009 (www.fao.org/fishery/statistics/software/fishstat/en.) Most of this dramatic increase can be accounted for by increases in production throughout Asia as they began to intensively culture Litopenaeus vannamei in lieu of the native Penaeus monodon, the black tiger shrimp, for export to the United States, specifically countries such as China, Thailand, Indonesia, and Vietnam. Fishery Statistical software 2009, supra. Following the introduction of Litopenaeus vannamei into Asia as a domesticated species, it became dominant, where in 2004 it accounted for half the shrimp produced globally. (Lightner, D. V., 2005. Biosecurity in shrimp farming: pathogen exclusion through use of SPF stock and routine surveillance. Journal of the World Aquaculture Society 36, 229-248.)
As L. vannamei began to dominate cultivation abroad, so did domestic demand in the United States. Shrimp imports rose from $1.6 billion to $3.7 billion from 1990-2004 (USDA Foreign Agriculture Service, 2005, US Seafood Imports Continue to Soar. International Trade Reports. Aug. 8, 2005. Jul. 28, 2010) representing 34 percent of total seafood imports and 25 percent of total seafood consumption in 2004, respectively. As of 2004, 70% of the United States seafood was imported with 40% of it being farm-raised, mostly cultured in southeast Asia. Rapidly increasing production of L. vannamei has outgrown demand, and led to price depression in international markets, mostly in the United States and European Union. Farm value for 15-20 g size Pacific White shrimp has steadily decreased from $5 US to about $3 in 2005. (Fisheries and Aquaculture Department, 2009, supra).
As farm raised production continues to increase in market share in comparison to wild stocks, so does the impact of disease on shrimp farming. Producers have adopted practices such as higher stocking densities, smaller inland pond culture, and higher feeding rates to increase competitiveness. This has led to an increasing vulnerability to infectious disease, specifically viral pathogens followed by secondary bacterial infections. Viral diseases such as White Spot Syndrome Virus (WSSV) have become pandemic and resulted in worldwide losses in the billions of dollars. For example, WSSV was first discovered in 1992 after several outbreaks of a high mortality disease occurred in shrimp farms in Taiwan (Chou, H.-Y., Huang, C.-Y., Wang, C.-H., Chiang, H.-C., Lo, C.-F., 1995. Pathogenicity of a baculovirus infection causing white spot syndrome in cultured penaeid shrimp in Taiwan. Diseases of Aquatic Organisms 23, 165-173.) It is estimated that Asia alone has lost over $6 billion since 1992, and the Americas $1-2 billion since WSSV was introduced in 1999 (Lightner 2003 The penaeid shrimp viral pandemics due to IHHNV, WSSV, TSV and YHV: history in the Americas and current status, Proceedings of the 32nd Joint UJNR Aquaculture Panel Symposium, Davis and Santa Barbara, Calif., USA, pp. 17-20.) In another example, Ecuador experienced dramatic losses, a 65% percent loss in production was observed after the introduction of WSSV and this accounted for, in lost exports alone, over a half billion US dollars. In addition, 130,000 jobs were lost and over 100,000 hectares of ponds were abandoned. (McClennen, C. White Spot Syndrome Virus, The Economic, Environmental and Technical Implications on the Development of Latin American Shrimp Farming. Master of Arts in Law and Diplomacy Thesis. 2004. http://fletcher.tufts.edu.)) Similarly, Peru experienced a precipitous drop in production to one tenth in 2000 of production in 1998 with 85% of shrimp ponds being abandoned, and $9 million in losses in feed costs alone. (McClennen, 2004, supra.) In China, it was estimated that 80% of total production losses annually were attributed to WSSV. (Zhan, W.-B., Wang, Y.-H., 1998. White Spot Syndrome Virus Infection of Cultured Shrimp in China. Journal of Aquatic Animal Health 10, 405-410.0
Currently there are no commercially available vaccines, therapeutics, or interventions for these pathogens causing devastating economic losses to aquatic invertebrates and in particular in shrimp producing countries.
All references cited are incorporated herein by reference in their entirety. Examples are provided by way of illustration and not intended to limit the scope of the invention.